CMAP_SET(3)

💾 CMAP_SET(3) — the Corosync Cluster Engine Programmer's Manual one

okay bestie, welcome to the <corosync/cmap.h> girlies' corner of the Corosync Cluster Engine Programmer's Manual 💖 this is cmap_set, page 3 of the manual, and she's here to help you store a value in CMAP. iconic behavior, truly.

✨ NAME ✨

cmap_set — Store value in CMAP 🫶

📜 SYNOPSIS 📜

First up, the main character:

#include <corosync/cmap.h>

cs_error_t cmap_set (cmap_handle_t handle, const char *key_name, const
void *value, size_t value_len, cmap_value_types_t type);

Also shortcuts for different types are defined 👑 — yes queen, one per type, because typing casts is not the vibe:

cs_error_t cmap_set_int8(cmap_handle_t handle, const char *key_name,
int8_t value);

cs_error_t cmap_set_uint8(cmap_handle_t handle, const char *key_name,
uint8_t value);

cs_error_t cmap_set_int16(cmap_handle_t handle, const char *key_name,
int16_t value);

cs_error_t cmap_set_uint16(cmap_handle_t handle, const char *key_name,
uint16_t value);

cs_error_t cmap_set_int32(cmap_handle_t handle, const char *key_name,
int32_t value);

cs_error_t cmap_set_uint32(cmap_handle_t handle, const char *key_name,
uint32_t value);

cs_error_t cmap_set_int64(cmap_handle_t handle, const char *key_name,
int64_t value);

cs_error_t cmap_set_uint64(cmap_handle_t handle, const char *key_name,
uint64_t value);

cs_error_t cmap_set_float(cmap_handle_t handle, const char *key_name,
float value);

cs_error_t cmap_set_double(cmap_handle_t handle, const char *key_name,
double value);

cs_error_t cmap_set_string(cmap_handle_t handle, const char *key_name,
const char *value);

💅 DESCRIPTION 💅

so the cmap_set function is the one that stores a key inside cmap. simple. elegant. she serves. ✨

let's break down her little ensemble:

• handle — this is your connection to the CMAP database, and you got it by calling cmap_initialize(3). no handle, no entry, periodt.
• key_name — the name of the key you're setting a value for. and bestie, she has rules: the key name is limited by a minimal length (CMAP_KEYNAME_MINLEN, currently 3) and a maximal length (CMAP_KEYNAME_MAXLEN, currently 255). also, the key can contain only a limited set of characters, expressed by this regexp: [a-zA-Z0-9._-/:]*. that's the whole guest list, nobody else gets in 🎀
• value — a pointer to the allocated data that will be stored inside CMAP. yes, allocated. we love a responsible memory moment.
• value_len — the length of value, measured in number of bytes. byte count, not vibes count.
• type — the last parameter, and she tells CMAP what kind of value this is. it may be one of:
  • CMAP_VALUETYPE_INT8 — 8-bit signed integer
  • CMAP_VALUETYPE_UINT8 — 8-bit unsigned integer
  • CMAP_VALUETYPE_INT16 — 16-bit signed integer
  • CMAP_VALUETYPE_UINT16 — 16-bit unsigned integer
  • CMAP_VALUETYPE_INT32 — 32-bit signed integer
  • CMAP_VALUETYPE_UINT32 — 32-bit unsigned integer
  • CMAP_VALUETYPE_INT64 — 64-bit signed integer
  • CMAP_VALUETYPE_UINT64 — 64-bit unsigned integer
  • CMAP_VALUETYPE_FLOAT — Float value
  • CMAP_VALUETYPE_DOUBLE — Double value
  • CMAP_VALUETYPE_STRING — C-style string
  • CMAP_VALUETYPE_BINARY — Binary data, byte with zero value has no special meaning

🚨 RETURN VALUE 🚨

okay so this call returns the CS_OK value if it's successful — that's your green flag, your little win, your slay 🌈

but sometimes she says no, and here's the whole tea:

• If value or key_name are unspecified, CS_ERR_INVALID_PARAM is returned. like, you have to actually give her something, bestie 😭
• Too short or too long key_name returns the CS_ERR_NAME_TOO_LONG error code. respect the length limits or get gently rejected.
• Some of keys may be tagged read-only directly in corosync, and setting such a key will result in a CS_ERR_ACCESS error. no means no, that key is not accepting edits today 💀

👀 SEE ALSO 👀

go read these next, iykyk:

• cmap_get(3)
• cmap_initialize(3)
• cmap_overview(3)

and here's the full error-code lineup, in case your call comes back looking a little different:

• CS_ERR_TRY_AGAIN — Resource temporarily unavailable
• CS_ERR_INVALID_PARAM — Invalid argument
• CS_ERR_ACCESS — Permission denied
• CS_ERR_LIBRARY — The connection failed
• CS_ERR_INTERRUPT — System call interrupted by a signal
• CS_ERR_NOT_SUPPORTED — The requested protocol/functionality not supported
• CS_ERR_MESSAGE_ERROR — Incorrect auth message received
• CS_ERR_NO_MEMORY — Not enough memory to complete the requested task

and that's the whole page, bestie 🧚 this was the corosync Man Page, dated 23/01/2012 — yes, she's an elder but she still eats 💜 go set some keys, and remember: check your return codes. mwah. 💅✨