34 lines
1.2 KiB
Groff
34 lines
1.2 KiB
Groff
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NAME
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putenv - change or add value to environment
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SYNTAX
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int putenv (string)
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char *string;
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DESCRIPTION
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String points to a string of the form ``name=value.''
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Putenv makes the value of the environment variable name
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equal to value by altering an existing variable or creating
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a new one. In either case, the string pointed to by string
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becomes part of the environment, so altering the string will
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change the environment. The space used by string is no
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longer used once a new string-defining name is passed to
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putenv.
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DIAGNOSTICS
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Putenv returns non-zero if it was unable to obtain enough
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space via malloc for an expanded environment, otherwise
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zero.
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SEE ALSO
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exec(2), getenv(3C), malloc(3C), environ(5).
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WARNINGS
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Putenv manipulates the environment pointed to by environ,
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and can be used in conjunction with getenv. However, envp
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(the third argument to main) is not changed.
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This routine uses malloc(3C) to enlarge the environment.
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After putenv is called, environmental variables are not in
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alphabetical order.
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A potential error is to call putenv with an automatic
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variable as the argument, then exit the calling function
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while string is still part of the environment.
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