rpma_log_set_function(3)

💖 rpma_log_set_function — bestie edition 💖

okay so this is a page from the RPMA Programmer's Manual, and today's main character is rpma_log_set_function(3). sit down, grab a boba, we're talking about where your logs go 🫶

---

✨ NAME ✨

rpma_log_set_function — set the logging function 💅

---

🌸 SYNOPSIS 🌸

#include <librpma.h>

typedef void rpma_log_function(
        enum rpma_log_level level,
        const char *file_name,
        const int line_no,
        const char *function_name,
        const char *message_format,
        ...);

int rpma_log_set_function(rpma_log_function *log_function);

like, that's the whole vibe. one function, one pointer, endless possibilities ✨

---

🦋 DESCRIPTION 🦋

so rpma_log_set_function() is literally your chance to pick which function gets handed every single logging message the library generates. no cap. all of them. it's giving "you are the chosen one" energy 👑

and log_function can be one of two things:

• RPMA_LOG_USE_DEFAULT_FUNCTION — which just uses the default logging function (built into the library, she's pre-installed bestie 💖)
• or a pointer to a user-defined function that you wrote yourself. main character move fr fr

so what do the parameters of a user-defined log function even look like? let me put you on:

• level — the log level of the message 📊
• file_name — name of the source file where the message coming from. lowkey important: it could be set to NULL, and in that case neither line_no nor function_name are provided. so like, be ready for that 💀
• line_no — the source file line where the message coming from 📍
• function_name — the function name where the message coming from 🎯
• message_format — a printf(3)-like format string of the message 🖨️
• "..." — additional arguments of the message format string 🎁

---

🎀 THE DEFAULT LOGGING FUNCTION 🎀

the initial value of the logging function is RPMA_LOG_USE_DEFAULT_FUNCTION. and what does that one do, you ask? she writes messages to syslog(3) (the primary destination) and to stderr(3) (the secondary destination). two destinations, one icon 🌈

---

⭐ RETURN VALUE ⭐

rpma_log_set_function() returns 0 on success or an error code on failure. simple as that bestie ✨

---

💀 ERRORS 💀

• RPMA_E_AGAIN — a temporary error occurred, the retry may fix the problem. so like, don't panic, just run it back 🔁

---

👑 NOTE 👑

the logging messages on the levels above the RPMA_LOG_THRESHOLD level won't trigger the logging function. so if you're wondering why your logs are ghosting you… that's why 🙈

also, the user defined function must be thread-safe. this is not a drill, this is not optional, this is the rule 📢

---

💜 SEE ALSO 💜

rpma_log_get_threshold(3), rpma_log_set_threshold(3), librpma(7) and https://pmem.io/rpma/ — go read them, they're the friend group 🫶

---

and that's the tea, bestie 🍓 this little gem comes to you from RPMA and it's dated 01 April 2024. now go forth and set your logging function like the icon you are 💅✨👑