bstr_printf(9)

💅 bstr_printf(9)

okay so welcome to bstr_printf(9) from the Kernel API Manual — yes bestie, the kernel has its own manual and we're reading it, main character energy fr fr ✨

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🌸 NAME

bstr_printf — format a string from binary arguments and place it in a buffer 🎀

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✨ SYNOPSIS

int bstr_printf (char *buf , size_t size , const char *fmt_str , const
       u32 *bin_buf );

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🦋 ARGUMENTS

• buf — the buffer you're dropping the result into 💌
• size — how big that buffer is, including the trailing null space (yes, the null counts, don't forget it 🙈)
• fmt_str — the format string you wanna use 🌈
• bin_buf — the binary arguments for that format string 🧚

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👑 DESCRIPTION

So this function is like C99 vsnprintf, but there's a difference: vsnprintf grabs its arguments off the stack, and bstr_printf grabs its arguments from bin_buf, which is a binary buffer that was generated by vbin_printf. it's giving "same vibe, different source" 💫

The format follows C99 vsnprintf, but it's got some extensions — see the vsnprintf comment for the details, iykyk 📝

Now, the return value: it's the number of characters which would be generated for the given input, excluding the trailing number of characters written into buf as return value (not including the trailing ' '), use vscnprintf. (yes, that trailing ' ' is literally how it's printed on the page — don't come for me, I'm just the messenger 💀)

⚠️ And listen: if the return is greater than or equal to size, the resulting string gets truncated. so keep an eye on that 👀

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🔥 SEE ALSO

Kernel file ./lib/vsprintf.c, plus: simple_strtoull(9), simple_strtoul(9), simple_strtol(9), simple_strtoll(9), vsnprintf(9), vscnprintf(9), snprintf(9), scnprintf(9), vsprintf(9), sprintf(9), vbin_printf(9), vsscanf(9), sscanf(9) 🌟

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and that's the page, bestie — brought to you from ./lib, dated October 2026, filed under bstr_printf(9). slay, go format something 💅💖