1 | /* This header file provides the reentrancy. */ |
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2 | |
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3 | /* The reentrant system calls here serve two purposes: |
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4 | |
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5 | 1) Provide reentrant versions of the system calls the ANSI C library |
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6 | requires. |
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7 | 2) Provide these system calls in a namespace clean way. |
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8 | |
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9 | It is intended that *all* system calls that the ANSI C library needs |
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10 | be declared here. It documents them all in one place. All library access |
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11 | to the system is via some form of these functions. |
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12 | |
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13 | The target may provide the needed syscalls by any of the following: |
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14 | |
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15 | 1) Define the reentrant versions of the syscalls directly. |
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16 | (eg: _open_r, _close_r, etc.). Please keep the namespace clean. |
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17 | When you do this, set "syscall_dir" to "syscalls" and add |
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18 | -DREENTRANT_SYSCALLS_PROVIDED to newlib_cflags in configure.host. |
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19 | |
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20 | 2) Define namespace clean versions of the system calls by prefixing |
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21 | them with '_' (eg: _open, _close, etc.). Technically, there won't be |
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22 | true reentrancy at the syscall level, but the library will be namespace |
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23 | clean. |
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24 | When you do this, set "syscall_dir" to "syscalls" in configure.host. |
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25 | |
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26 | 3) Define or otherwise provide the regular versions of the syscalls |
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27 | (eg: open, close, etc.). The library won't be reentrant nor namespace |
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28 | clean, but at least it will work. |
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29 | When you do this, add -DMISSING_SYSCALL_NAMES to newlib_cflags in |
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30 | configure.host. |
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31 | |
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32 | 4) Define or otherwise provide the regular versions of the syscalls, |
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33 | and do not supply functional interfaces for any of the reentrant |
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34 | calls. With this method, the reentrant syscalls are redefined to |
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35 | directly call the regular system call without the reentrancy argument. |
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36 | When you do this, specify both -DREENTRANT_SYSCALLS_PROVIDED and |
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37 | -DMISSING_SYSCALL_NAMES via newlib_cflags in configure.host and do |
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38 | not specify "syscall_dir". |
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39 | |
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40 | Stubs of the reentrant versions of the syscalls exist in the libc/reent |
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41 | source directory and are provided if REENTRANT_SYSCALLS_PROVIDED isn't |
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42 | defined. These stubs call the native system calls: _open, _close, etc. |
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43 | if MISSING_SYSCALL_NAMES is *not* defined, otherwise they call the |
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44 | non-underscored versions: open, close, etc. when MISSING_SYSCALL_NAMES |
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45 | *is* defined. |
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46 | |
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47 | By default, newlib functions call the reentrant syscalls internally, |
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48 | passing a reentrancy structure as an argument. This reentrancy structure |
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49 | contains data that is thread-specific. For example, the errno value is |
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50 | kept in the reentrancy structure. If multiple threads exist, each will |
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51 | keep a separate errno value which is intuitive since the application flow |
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52 | cannot check for failure reliably otherwise. |
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53 | |
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54 | The reentrant syscalls are either provided by the platform, by the |
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55 | libc/reent stubs, or in the case of both MISSING_SYSCALL_NAMES and |
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56 | REENTRANT_SYSCALLS_PROVIDED being defined, the calls are redefined to |
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57 | simply call the regular syscalls with no reentrancy struct argument. |
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58 | |
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59 | A single-threaded application does not need to worry about the reentrancy |
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60 | structure. It is used internally. |
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61 | |
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62 | A multi-threaded application needs either to manually manage reentrancy |
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63 | structures or use dynamic reentrancy. |
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64 | |
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65 | Manually managing reentrancy structures entails calling special reentrant |
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66 | versions of newlib functions that have an additional reentrancy argument. |
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67 | For example, _printf_r. By convention, the first argument is the |
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68 | reentrancy structure. By default, the normal version of the function |
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69 | uses the default reentrancy structure: _REENT. The reentrancy structure |
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70 | is passed internally, eventually to the reentrant syscalls themselves. |
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71 | How the structures are stored and accessed in this model is up to the |
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72 | application. |
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73 | |
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74 | Dynamic reentrancy is specified by the __DYNAMIC_REENT__ flag. This |
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75 | flag denotes setting up a macro to replace _REENT with a function call |
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76 | to __getreent(). This function needs to be implemented by the platform |
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77 | and it is meant to return the reentrancy structure for the current |
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78 | thread. When the regular C functions (e.g. printf) go to call internal |
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79 | routines with the default _REENT structure, they end up calling with |
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80 | the reentrancy structure for the thread. Thus, application code does not |
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81 | need to call the _r routines nor worry about reentrancy structures. */ |
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82 | |
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83 | /* WARNING: All identifiers here must begin with an underscore. This file is |
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84 | included by stdio.h and others and we therefore must only use identifiers |
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85 | in the namespace allotted to us. */ |
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86 | |
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87 | #ifndef _REENT_H_ |
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88 | #ifdef __cplusplus |
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89 | extern "C" { |
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90 | #endif |
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91 | #define _REENT_H_ |
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92 | |
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93 | #include <sys/reent.h> |
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94 | #include <sys/_types.h> |
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95 | |
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96 | #define __need_size_t |
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97 | #define __need_ptrdiff_t |
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98 | #include <stddef.h> |
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99 | |
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100 | /* FIXME: not namespace clean */ |
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101 | struct stat; |
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102 | struct tms; |
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103 | struct timeval; |
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104 | struct timezone; |
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105 | |
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106 | #if defined(REENTRANT_SYSCALLS_PROVIDED) && defined(MISSING_SYSCALL_NAMES) |
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107 | |
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108 | #define _close_r(__reent, __fd) close(__fd) |
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109 | #define _execve_r(__reent, __f, __arg, __env) execve(__f, __arg, __env) |
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110 | #define _fcntl_r(__reent, __fd, __cmd, __arg) fcntl(__fd, __cmd, __arg) |
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111 | #define _fork_r(__reent) fork() |
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112 | #define _fstat_r(__reent, __fdes, __stat) fstat(__fdes, __stat) |
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113 | #define _getpid_r(__reent) getpid() |
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114 | #define _isatty_r(__reent, __desc) isatty(__desc) |
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115 | #define _kill_r(__reent, __pid, __signal) kill(__pid, __signal) |
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116 | #define _link_r(__reent, __oldpath, __newpath) link(__oldpath, __newpath) |
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117 | #define _lseek_r(__reent, __fdes, __off, __w) lseek(__fdes, __off, __w) |
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118 | #define _mkdir_r(__reent, __path, __m) mkdir(__path, __m) |
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119 | #define _open_r(__reent, __path, __flag, __m) open(__path, __flag, __m) |
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120 | #define _read_r(__reent, __fd, __buff, __cnt) read(__fd, __buff, __cnt) |
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121 | #define _rename_r(__reent, __old, __new) rename(__old, __new) |
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122 | #define _sbrk_r(__reent, __incr) sbrk(__incr) |
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123 | #define _stat_r(__reent, __path, __buff) stat(__path, __buff) |
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124 | #define _times_r(__reent, __time) times(__time) |
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125 | #define _unlink_r(__reent, __path) unlink(__path) |
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126 | #define _wait_r(__reent, __status) wait(__status) |
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127 | #define _write_r(__reent, __fd, __buff, __cnt) write(__fd, __buff, __cnt) |
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128 | #define _gettimeofday_r(__reent, __tp, __tzp) gettimeofday(__tp, __tzp) |
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129 | |
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130 | #ifdef __LARGE64_FILES |
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131 | #define _lseek64_r(__reent, __fd, __off, __w) lseek64(__fd, __off, __w) |
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132 | #define _fstat64_r(__reent, __fd, __buff) fstat64(__fd, __buff) |
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133 | #define _open64_r(__reent, __path, __flag, __m) open64(__path, __flag, __m) |
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134 | #endif |
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135 | |
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136 | #else |
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137 | /* Reentrant versions of system calls. */ |
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138 | |
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139 | extern int _close_r (struct _reent *, int); |
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140 | extern int _execve_r (struct _reent *, const char *, char *const *, char *const *); |
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141 | extern int _fcntl_r (struct _reent *, int, int, int); |
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142 | extern int _fork_r (struct _reent *); |
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143 | extern int _fstat_r (struct _reent *, int, struct stat *); |
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144 | extern int _getpid_r (struct _reent *); |
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145 | extern int _isatty_r (struct _reent *, int); |
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146 | extern int _kill_r (struct _reent *, int, int); |
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147 | extern int _link_r (struct _reent *, const char *, const char *); |
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148 | extern _off_t _lseek_r (struct _reent *, int, _off_t, int); |
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149 | extern int _mkdir_r (struct _reent *, const char *, int); |
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150 | extern int _open_r (struct _reent *, const char *, int, int); |
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151 | extern _ssize_t _read_r (struct _reent *, int, void *, size_t); |
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152 | extern int _rename_r (struct _reent *, const char *, const char *); |
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153 | extern void *_sbrk_r (struct _reent *, ptrdiff_t); |
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154 | extern int _stat_r (struct _reent *, const char *, struct stat *); |
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155 | extern _CLOCK_T_ _times_r (struct _reent *, struct tms *); |
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156 | extern int _unlink_r (struct _reent *, const char *); |
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157 | extern int _wait_r (struct _reent *, int *); |
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158 | extern _ssize_t _write_r (struct _reent *, int, const void *, size_t); |
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159 | |
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160 | /* This one is not guaranteed to be available on all targets. */ |
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161 | extern int _gettimeofday_r (struct _reent *, struct timeval *__tp, void *__tzp); |
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162 | |
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163 | #ifdef __LARGE64_FILES |
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164 | |
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165 | |
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166 | #if defined(__CYGWIN__) |
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167 | #define stat64 stat |
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168 | #endif |
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169 | struct stat64; |
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170 | |
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171 | extern _off64_t _lseek64_r (struct _reent *, int, _off64_t, int); |
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172 | extern int _fstat64_r (struct _reent *, int, struct stat64 *); |
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173 | extern int _open64_r (struct _reent *, const char *, int, int); |
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174 | extern int _stat64_r (struct _reent *, const char *, struct stat64 *); |
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175 | |
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176 | /* Don't pollute namespace if not building newlib. */ |
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177 | #if defined (__CYGWIN__) && !defined (_COMPILING_NEWLIB) |
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178 | #undef stat64 |
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179 | #endif |
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180 | |
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181 | #endif |
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182 | |
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183 | #endif |
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184 | |
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185 | #ifdef __cplusplus |
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186 | } |
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187 | #endif |
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188 | #endif /* _REENT_H_ */ |
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