### C Library Functions: Environment Interaction

Function | Header File | Description
abort | stdlib.h process.h | Terminates a program abnormally.
exit | stdlib.h process.h | Ends a program normally.
getenv | stdlib.h | Searches environment variables for a specified variable.
longjmp | setjmp.h | Restores a stack environment.
__parmdwords | stdlib.h | Returns the hidden parameter passed in the AL register for functions with the _System calling convention.
putenv | stdlib.h | Adds new environment variables, or modifies the values of those already existing.
setjmp | setjmp.h | Saves a stack environment.
system | stdlib.h process.h | Passes a string to the operating system's command interpreter.

Setting and Querying Locale

Function | Header File | Description
csid | stdlib.h | Determines the character set identifier for a character.
getsyntx | variant.h | Determines the encoding of special characters in the LC_SYNTAX locale category.
localdtconv | locale.h | Queries the date and time formatting conventions for the current locale.
localeconv | locale.h | Queries the numeric formatting conventions for the current locale.
nl_langinfo | langinfo.h | Retrieves requested information for the current locale.
setlocale | locale.h | Changes or queries the locale.
wcsid | stdlib.h | Determines the character set identifier for a wide character.

Converting characters to another code set

Function | Header File | Description
ccsidtocs | iconv.h | Determines the code page name for a coded character set ID.
cstoccsid | iconv.h | Determines the coded character set ID for a code page name.
iconv | iconv.h | Converts characters from one codeset to another.
iconv_close | iconv.h | Deletes the conversion descriptor created by iconv_open.
iconv_open | iconv.h | Creates a conversion descriptor for iconv to use in converting characters.

Alphabetical Listing of IBM C and C++ Compilers Functions and Macros