= The stdlib library =

The [source:soft/giet_vm/giet_libs/stdlib.c stdlib.c] and [source:soft/giet_vm/giet_libs/stdlib.h stdlib.h] 
files define a set of useful functions that do not require a system call.

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 == int '''atoi'''( char * string ) ==
This function translate a character string to a signed integer. All characters (but the first) must be digits.
For a negative value, the  first character must be the '-' (minus) character.

 == double '''atof'''( char * string ) ==
This function translate a character string to a double. Conversion stop at first non-numeric character (except a first '+' or '-' and one '.').

 == void* '''memcpy'''( void* dst, const void* src, unsigned int size ) ==
This function copies ''size'' bytes from the ''src'' source buffer to the ''dst'' destination buffer.

 == void* '''memset'''( void* dst , int s , unsigned int size ) ==
This function initializes ''size'' bytes in the ''dst'' destination buffer, with the value defined by ''(char)s''.

 == unsigned int '''strlen'''( char* string ) ==
This function returns the number of characters in a string. The terminating NUL character is not taken into account.

 == unsigned int '''strcmp'''( char* s1 , char* s2 ) ==
This function compare the two s1 & s2 strings.It returns 0 if strings are identical (including the terminating NUL character), 
and returns 1 if they are not. 

 == unsigned int '''strcpy'''( char* dest , char* source ) ==
This function copies the source string to the dest string.It returns a pointer on the dest string.

 == unsigned int '''snprintf'''( char* string , unsigned int maxlen , char* format , va_list* args ) ==
This function can be directly used by an application to build a formated string.
It is also used the ''giet_tty_printf()'' and ''giet_fat_printf()'' system calls.
It analyse the <format> and <args> arguments and returns a byte stream
in the <stream> buffer. The TO_STREAM macro checks buffer overflow.
It returns number of written bytes in case of success.
It returns 0xFFFFFFFF in case of error (illegal format, or buffer overflow).