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1 # Formatting |
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2 |
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3 In the `printf.h` header you can find various useful `printf()`-like functions that can write the formatted output |
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4 directly to an arbitrary stream or [buffer](buffer.h.md), or to memory allocated by an [allocator](allocator.h.md). |
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5 |
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6 With the help of these convenience functions, you do not need the libc `snprintf` to print your string to a temporary buffer anymore, |
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7 plus you do not need to worry about too small buffer sizes, because the functions will automatically allocate enough memory to contain the entire formatted string. |
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8 |
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9 ## Print to Streams and Buffers |
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10 |
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11 ```C |
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12 #include <cx/printf.h> |
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13 |
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14 int cx_fprintf(void *stream, cx_write_func wfc, |
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15 const char *fmt, ...); |
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16 |
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17 int cx_vfprintf(void *stream, cx_write_func wfc, |
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18 const char *fmt, va_list ap); |
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19 |
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20 int cx_bprintf(CxBuffer *buf, const char *fmt, ...); |
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21 ``` |
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22 |
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23 > TODO: document |
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24 {style="warning"} |
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25 |
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26 The `cx_vfprintf()` function is equivalent to `cx_fprintf()`, |
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27 except that instead of being called with a variable number of arguments, |
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28 they are called with an argument list as defined by `<stdarg.h>`. |
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29 |
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30 ## Print to Freshly Allocated Memory |
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31 |
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32 ```C |
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33 #include <cx/printf.h> |
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34 |
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35 cxmutstr cx_asprintf(const char *fmt, ...); |
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36 |
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37 cxmutstr cx_asprintf_a(const CxAllocator *allocator, |
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38 const char *fmt, ...); |
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39 |
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40 cxmutstr cx_vasprintf(const char *fmt, va_list ap); |
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41 |
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42 cxmutstr cx_vasprintf_a(const CxAllocator *allocator, |
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43 const char *fmt, va_list ap); |
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44 ``` |
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45 |
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46 > TODO: document |
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47 {style="warning"} |
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48 |
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49 The `cx_vasprintf()` and `cx_vasprintf_a()` functions are equivalent to `cx_asprintf()` and `cx_asprintf_a()`, |
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50 except that instead of being called with a variable number of arguments, |
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51 they are called with an argument list as defined by `<stdarg.h>`. |
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52 |
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53 ## Print to Existing Memory |
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54 |
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55 ```C |
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56 #include <cx/printf.h> |
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57 |
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58 cx_sprintf |
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59 cx_sprintf_a |
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60 cx_sprintf_s |
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61 cx_sprintf_sa |
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62 cx_vsprintf |
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63 cx_vsprintf_a |
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64 cx_vsprintf_s |
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65 cx_vsprintf_sa |
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66 ``` |
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67 |
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68 > TODO: document |
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69 {style="warning"} |
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70 |
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71 The `cx_vsprintf()`, `cx_vsprintf_a()`, `cx_vsprintf_s()`, and `cx_vsprintf_sa()` functions are equivalent |
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72 to `cx_sprintf()`, `cx_sprintf_a()`, `cx_sprintf_s()`, and `cx_sprintf_sa()`, |
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73 except that instead of being called with a variable number of arguments, |
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74 they are called with an argument list as defined by `<stdarg.h>`. |
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75 |
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76 ## Small Buffer Optimization |
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77 |
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78 All functions that allocate internal temporary memory use small buffer optimization to avoid a heap allocation |
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79 if the expected string length is smaller than `cx_printf_sbo_size`. |
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80 This size cannot be changed at runtime, but modified by defining the `CX_PRINTF_SBO_SIZE` macro when [building](install.md#small-buffer-optimizations) the library. |
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81 |
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82 <seealso> |
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83 <category ref="apidoc"> |
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84 <a href="https://ucx.sourceforge.io/api/printf_8h.html">printf.h</a> |
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85 </category> |
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86 </seealso> |
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87 |