tools/counter/counter_example.c
Source file repositories/reference/linux-study-clean/tools/counter/counter_example.c
File Facts
- System
- Linux kernel
- Corpus path
tools/counter/counter_example.c- Extension
.c- Size
- 2215 bytes
- Lines
- 93
- Domain
- Support Tooling And Documentation
- Bucket
- tools
- Inferred role
- Support Tooling And Documentation: implementation source
- Status
- source implementation candidate
Why This File Exists
Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.
- Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.
- Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.
Dependency Surface
errno.hfcntl.hlinux/counter.hstdio.hstring.hsys/ioctl.hunistd.h
Detected Declarations
function main
Annotated Snippet
if (ret == -1) {
fprintf(stderr, "Error adding watches[%d]: %s\n", i,
strerror(errno));
return 1;
}
}
ret = ioctl(fd, COUNTER_ENABLE_EVENTS_IOCTL);
if (ret == -1) {
perror("Error enabling events");
return 1;
}
for (;;) {
ret = read(fd, event_data, sizeof(event_data));
if (ret == -1) {
perror("Failed to read event data");
return 1;
}
if (ret != sizeof(event_data)) {
fprintf(stderr, "Failed to read event data\n");
return -EIO;
}
printf("Timestamp 0: %llu\tCount 0: %llu\n"
"Error Message 0: %s\n"
"Timestamp 1: %llu\tCount 1: %llu\n"
"Error Message 1: %s\n",
event_data[0].timestamp, event_data[0].value,
strerror(event_data[0].status),
event_data[1].timestamp, event_data[1].value,
strerror(event_data[1].status));
}
return 0;
}
Annotation
- Immediate include surface: `errno.h`, `fcntl.h`, `linux/counter.h`, `stdio.h`, `string.h`, `sys/ioctl.h`, `unistd.h`.
- Detected declarations: `function main`.
- Atlas domain: Support Tooling And Documentation / tools.
- Implementation status: source implementation candidate.
Implementation Notes
- This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
- Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
- Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.