zkStdlib.h is a portable wrapper for the Standard C header <stdlib.h>. It is part of the libzk library because there are parts of the Zero Knowledge code base that assume it contains functionality beyond that provided by Standard C, namely POSIX or platform-specific features.

zkStdlib.h - Supported Macros from <stdlib.h>
Macro Description
EXIT_FAILURE Unsuccessful termination for exit(), evaluates to a non-zero value.
EXIT_SUCCESS Successful termination for exit(), evaluates to 0.
RAND_MAX Maximum value returned by rand(), at least 32,767.

zkStdlib.h - Supported Types from <stdlib.h>
Type Description
div_t, a struct with members:  
int quot
 
int rem
 
ldiv_t, a struct with members:  
long int quot
 
long int rem
 

zkStdlib.h - Supported Functions from <stdlib.h>
abort
abs
atexit
atof
atoi
atol
bsearch
div
exit
labs
ldiv
qsort
rand
srand
strtod
strtol
strtoul

zkStdlib.h - Deprecated Functions from <stdlib.h>
Don't Call This Instead, Call This Reason
calloc zkCalloc Standard C doesn't define calloc as setting errno.
free zkFree For consistency with zkCalloc, zkMalloc, and zkRealloc.
malloc zkMalloc Standard C doesn't define malloc as setting errno.
realloc zkRealloc Standard C doesn't define realloc as setting errno.