1unsetenv(3C)             Standard C Library Functions             unsetenv(3C)
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NAME

6       unsetenv - remove an environment variable
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SYNOPSIS

9       #include <stdlib.h>
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11       int unsetenv(const char *name);
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DESCRIPTION

15       The  unsetenv() function removes an environment variable from the envi‐
16       ronment of the calling process. The name argument points  to  a  string
17       that is the name of the variable to be removed. The named argument can‐
18       not contain an '=' character. If the named variable does not  exist  in
19       the  current environment, the environment is unchanged and the function
20       is considered to have completed successfully.
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23       If the application modifies environ or the pointers to which it points,
24       the  behavior  of  unsetenv()  is  undefined.  The  unsetenv() function
25       updates the list of pointers to which environ points.
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RETURN VALUES

28       Upon successful completion, 0 is returned. Otherwise, -1  is  returned,
29       errno set to indicate the error, and the environment is left unchanged.
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ERRORS

32       The unsetenv() function will fail if:
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34       EINVAL    The  name  argument  is  a  null  pointer, points to an empty
35                 string, or points to a string containing an '=' character.
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ATTRIBUTES

39       See attributes(5) for descriptions of the following attributes:
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44       ┌─────────────────────────────┬─────────────────────────────┐
45       │      ATTRIBUTE TYPE         │      ATTRIBUTE VALUE        │
46       ├─────────────────────────────┼─────────────────────────────┤
47       │Interface Stability          │Standard                     │
48       ├─────────────────────────────┼─────────────────────────────┤
49       │MT-Level                     │MT-Safe                      │
50       └─────────────────────────────┴─────────────────────────────┘
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SEE ALSO

53       getenv(3C), setenv(3C), attributes(5), standards(5)
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57SunOS 5.11                        1 Nov 2003                      unsetenv(3C)
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