Compaq C
Run-Time Library Reference Manual for OpenVMS Systems

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`__STDC_VERSION__` macro
`_ANSI_C_SOURCE` macro
`_BSD44_CURSES` macro
`_DECC_V4_SOURCE` macro
`_exit` function #1
`_exit` function #2
`_POSIX_C_SOURCE` macro
`_SOCKADDR_LEN` macro
`_tolower` function
`_tolower` macro
`_toupper` function
`_toupper` macro
`_VMS_CURSES` macro
`_VMS_V6_SOURCE` macro
`_XOPEN_SOURCE` macro
`_XOPEN_SOURCE_EXTENDED`XOPEN_SOURCE_EXTENDED

Compaq CRun-Time Library Reference Manual for OpenVMS Systems