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clearenv |
Portability: | POSIX.1 conforming |
SYNOPSIS | |
DESCRIPTION | |
RETURN VALUE | |
CAUTION | |
EXAMPLE | |
RELATED FUNCTIONS | |
SEE ALSO |
SYNOPSIS |
#include <env.h> int clearenv(void);
DESCRIPTION |
clearenv
deletes the environment-variable list for a process. Only program-scope environment
variables are affected.
RETURN VALUE |
clearenv
returns 0 if it is successful and -1 if it is not successful.
CAUTION |
A copy of the
environ
pointer may not be valid after a call is made to
clearenv
.
EXAMPLE |
The following code fragment illustrates
the use of
clearenv
:
/* This example requires compilation with the posix option */ /* to execute successfully. */ #include <stdlib.h> #include <stdio.h> extern char **environ; int count_env() { int num; for (num=0; environ[num] !=NULL; num++); return num; } . . . printf("There are %d environment variables\n", count_env()); if (clearenv() !=0) perror("clearenv() error"); else { printf("Now there are %d environment variables\n", count_env()); } . . .
RELATED FUNCTIONS |
SEE ALSO |
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