ISO/IEC TR 24731-1:2007为C库（定义见ISO/IEC 9899:1999）提供了替代功能，以促进更安全、更安全的编程。这些函数验证输出缓冲区是否足够大以达到预期的结果，如果没有足够大，则返回故障指示器。或者，失败的函数调用“运行时约束处理程序”来报告错误。数据永远不会写入数组的末尾。所有字符串结果都以null结尾。此外，ISO/IEC TR 24731-1:2007中的函数是可重入的:它们从不返回指向该函数所拥有的静态对象的指针。 ISO/IEC TR 24731-1:2007还包含解决C输入不安全问题的函数- 输出设备。

ISO/IEC TR 24731-1:2007 provides alternative functions for the C Library (as defined in ISO/IEC 9899:1999) that promote safer, more secure programming. The functions verify that output buffers are large enough for the intended result, and return a failure indicator if they are not. Optionally, failing functions call a "runtime-constraint handler" to report the error. Data is never written past the end of an array. All string results are null terminated. In addition, the functions in ISO/IEC TR 24731-1:2007 are re-entrant: they never return pointers to static objects owned by the function. ISO/IEC TR 24731-1:2007 also contains functions that address insecurities with the C input-output facilities.