I/O Functions¶
Introduction¶
qgenlib provides functions for basic input/output functions to handle messages to print out during the program execution.
Error, Warning, and Notification Messages¶
Users can output printf-style functions, with variable number of arguments, to output error, warning, and notification messages. This function acts like fprintf in the sense that the message is printed to the standard error output, with the following differences:
notice()function automatically prints the timestamp before each message.warning()function automatically prints the timestamp, give a beep sound, and prints and the word "WARNING" before each message.error()function prints out the error message and terminate the program.
Below are examples of how to use these functions:
// int n : number of lines processed
notice("Processed %d lines of input lines\n", n);
// Example output:
// NOTICE [2024/02/29 14:21:09] - Processed 1000 lines of input lines
// int n : current line number
warning("Line %d is not properly formatted\n", n);
// Example output: (with beep)
// WARNING [2024/02/29 14:21:09] - Line 1234 is not properly formatted
// int n : current line number
error("Cannot parse line %d\n", n);
// Example output: (exits the program)
// FATAL ERROR -
// Cannot parse line 1234
Some of these examples can also be found in the qbcf repository in the qbcf test-qgenlib tool.
Other printf-style Functions¶
qgenlib also provides other printf-style functions to handle messages.
catprintf()function appends printf-style string to the current string.hprintf()function write messages tohtsFile*object.
// append a string to a std::string object in print-style
std::string str("Hello");
int num = 1234;
std::string name("Customer");
// str will contains "Hello, Customer No. 1234" after running the following line
catprintf(str, ", %s No. %d", name.c_str(), num);
// write a message to a htsFile* object in printf-style
htsFile* fp = hts_open("output.txt", "w");
hprintf(fp, "Hello, %s No. %d", name.c_str(), num);
hts_close(fp);