# nng_ctx_setopt(3) Manual Page

## NAME

nng_ctx_setopt - set context option

## SYNOPSIS

    #include <nng/nng.h>

    int nng_ctx_setopt(nng_ctx ctx, const char *opt, const void *val, size_t valsz);

    int nng_ctx_setopt_bool(nng_ctx ctx, const char *opt, int bval);

    int nng_ctx_setopt_int(nng_ctx ctx, const char *opt, int ival);

    int nng_ctx_setopt_ms(nng_ctx ctx, const char *opt, nng_duration dur);

    int nng_ctx_setopt_size(nng_ctx ctx, const char *opt, size_t z);

    int nng_ctx_setopt_string(nng_ctx ctx, const char *opt, const char *str);

    int nng_ctx_setopt_uint64(nng_ctx ctx, const char *opt, uint64_t u64);

## DESCRIPTION

| These functions are deprecated. Please see nng_ctx_set. They may not be present if the library was built with `NNG_ELIDE_DEPRECATED`.

The `nng_ctx_setopt()` functions are used to configure options for the context ctx. The actual options that may be configured in this way vary, and are specified by opt.

| Context options are protocol specific. The details will be documented with the protocol.

### Forms

The details of the type, size, and semantics of the option will depend on the actual option, and will be documented with the option itself.

`nng_ctx_setopt()`

  This function is untyped, and can be used to configure any arbitrary data. The val pointer addresses the data to copy, and valsz is the size of the objected located at val.

| It may be easier to use one of the typed forms of this function.

`nng_ctx_setopt_bool()`

  This function is for options which take a Boolean (`bool`). The bval is passed to the option.

`nng_ctx_setopt_int()`

  This function is for options which take an integer (`int`). The ival is passed to the option.

`nng_ctx_setopt_ms()`

  This function is used to configure time durations (such as timeouts) using type `nng_duration`. The duration dur is an integer number of milliseconds.

`nng_ctx_setopt_size()`

  This function is used to configure a size, z, typically for buffer sizes, message maximum sizes, and similar options.

`nng_ctx_setopt_string()`

  This function is used to pass configure a string, str. Strings passed this way must be legal UTF-8 or ASCII strings, terminated with a `NUL` (`\0`) byte. (Other constraints may apply as well, see the documentation for each option for details.)

`nng_ctx_setopt_uint64()`

  This function is used to configure a 64-bit unsigned value, u64. This is typically used for options related to identifiers, network numbers, and similar.

## RETURN VALUES

These functions return 0 on success, and non-zero otherwise.

## ERRORS

`NNG_ECLOSED` | Parameter s does not refer to an open socket.
`NNG_EINVAL` | The value being passed is invalid.
`NNG_ENOTSUP` | The option opt is not supported.
`NNG_EREADONLY` | The option opt is read-only.
`NNG_ESTATE` | The socket is in an inappropriate state for setting this option.

## SEE ALSO

nng_ctx_getopt(3), nng_setopt(3), nng_strerror(3), nng_ctx(5), nng_options(5), nng_socket(5), nng(7)