# xvsnprintf

- **Language:** C
- **Kind:** function
- **Source:** https://github.com/tmux/tmux/blob/e476c1230b958df0cb12977517d24b3dc931375b/xmalloc.c#L148
- **Page:** https://libtmux.org/en/tmux/3.7c/reference/c-function-xvsnprintf/

```c
int xvsnprintf(char *str, size_t len, const char *fmt, va_list ap)
```

## Parameters

- `str` (`char *`)
- `len` (`size_t`)
- `fmt` (`const char *`)
- `ap` (`va_list`)

## Called by

- [`xsnprintf`](/en/tmux/3.7c/reference/c-function-xsnprintf/) (function) [Call site](https://github.com/tmux/tmux/blob/e476c1230b958df0cb12977517d24b3dc931375b/xmalloc.c#L141)

## Calls

- [`fatalx`](/en/tmux/3.7c/reference/c-function-fatalx/) (function) [Call site](https://github.com/tmux/tmux/blob/e476c1230b958df0cb12977517d24b3dc931375b/xmalloc.c#L153)