Reference
C Library
IOstream Library
Strings library
STL Containers
STL Algorithms
Miscellaneous
C Library
cassert (assert.h)
cctype (ctype.h)
cerrno (errno.h)
cfloat (float.h)
ciso646 (iso646.h)
climits (limits.h)
clocale (locale.h)
cmath (math.h)
csetjmp (setjmp.h)
csignal (signal.h)
cstdarg (stdarg.h)
cstddef (stddef.h)
cstdio (stdio.h)
cstdlib (stdlib.h)
cstring (string.h)
ctime (time.h)
cstdlib (stdlib.h)
functions:
abort
abs
atexit
atof
atoi
atol
bsearch
calloc
div
exit
free
getenv
labs
ldiv
malloc
mblen
mbstowcs
mbtowc
qsort
rand
realloc
srand
strtod
strtol
strtoul
system
wcstombs
wctomb
functions (non-standard):
itoa
macros:
EXIT_FAILURE
EXIT_SUCCESS
MB_CUR_MAX
NULL
RAND_MAX
types:
div_t
ldiv_t
size_t


getenv

function
<cstdlib>
char * getenv ( const char * name );

Get environment string

Retrieves a C string containing the value of the environment variable whose name is specified as argument. If the requested variable is not part of the environment list, the function returns a NULL pointer.

The string pointed by the pointer returned by this function shall not be modified by the program.

The same memory location may be used in subsequent calls to getenv, overwriting the previous content.

Parameters

name
C string containing the name of the requested variable.

Return Value

A null-terminated string with the value of the requested environment variable, or NULL if that environment variable does not exist.

Portability

Depending on the platform, this function may either be or not be case sensitive.

Example

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/* getenv example: getting path */
#include <stdio.h>
#include <stdlib.h>
int main ()
{
  char * pPath;
  pPath = getenv ("PATH");
  if (pPath!=NULL)
    printf ("The current path is: %s",pPath);
  return 0;
}

The example above prints the PATH environment variable.

See also

system Execute system command (function)