The function fgets is used in the C programming language to read a line of text from a specified input stream, such as a file or standard input. It reads characters until a newline character is encountered, the end of the file is reached, or a specified number of characters is read. This function is useful for capturing user input or reading data from files while ensuring that the input does not exceed a predetermined length. When using fgets, the programmer must provide a buffer to store the input, the maximum number of characters to read, and the input stream. It is important to note that fgets includes the newline character in the buffer if it is encountered, which can affect how the input is processed later. Proper handling of the buffer and newline character is essential for effective input management in C programs.