Type:	Package
Title:	R and C++ Interfaces to 'spdlog' C++ Header Library for Logging
Version:	0.0.23
Date:	2025-10-11
License:	GPL-2 | GPL-3 [expanded from: GPL (≥ 2)]
Description:	The mature and widely-used C++ logging library 'spdlog' by Gabi Melman provides many desirable features. This package bundles these header files for easy use by R packages from both their R and C or C++ code. Explicit use via 'LinkingTo:' is also supported. Also see the 'spdl' package which enhanced this package with a consistent R and C++ interface.
URL:	https://github.com/eddelbuettel/rcppspdlog, https://eddelbuettel.github.io/rcppspdlog/, https://dirk.eddelbuettel.com/code/rcpp.spdlog.html
BugReports:	https://github.com/eddelbuettel/rcppspdlog/issues
LinkingTo:	Rcpp
Imports:	Rcpp
Suggests:	simplermarkdown
VignetteBuilder:	simplermarkdown
RoxygenNote:	6.0.1
NeedsCompilation:	yes
Packaged:	2025-10-11 14:33:29 UTC; edd
Author:	Dirk Eddelbuettel [aut, cre], Gabi Melman [aut] (Author of spdlog), Victor Zverovic [aut] (Author of fmt)
Maintainer:	Dirk Eddelbuettel <edd@debian.org>
Repository:	CRAN
Date/Publication:	2025-10-12 05:10:02 UTC

R and C++ Interfaces to 'spdlog' C++ Header Library for Logging

Description

The mature and widely-used C++ logging library 'spdlog' by Gabi Melman provides many desirable features. This package bundles these header files for easy use by R packages from both their R and C or C++ code. Explicit use via 'LinkingTo:' is also supported. Also see the 'spdl' package which enhanced this package with a consistent R and C++ interface.

Details

The DESCRIPTION file:

Index of help topics:

RcppSpdlog-package      R and C++ Interfaces to 'spdlog' C++ Header
                        Library for Logging
exampleRsink            spdlog Example using a sink for R
formatter               Simple Pass-Through Formatter to
                        'fmt::format()'
get_stopwatch           R Accessor Functions for spdlog Stopwatch
log_setup               R Accessor Functions for spdlog Logger
setLogLevel             spdlog Logging Lever Setter

This section should provide a more detailed overview of how to use the package, including the most important functions.

Author(s)

Dirk Eddelbuettel [aut, cre] (ORCID: <https://orcid.org/0000-0001-6419-907X>), Gabi Melman [aut] (Author of spdlog), Victor Zverovic [aut] (Author of fmt)

Maintainer: Dirk Eddelbuettel <edd@debian.org>

spdlog Example using a sink for R

Description

A simple example invoking a derived R/Rcpp logger. Also demonstrates the stopwatch feature. For more features see the 'spdlog' documnetation.

Usage

exampleRsink()

Details

Note that this no longer triggers R warnings thanks to excellent help by Gabi Melman.

Value

None

Examples

exampleRsink()

Simple Pass-Through Formatter to fmt::format()

Description

The C-level interface of R does not make it easy to pass ... arguments. This helper function assumes it has already been called with format() on each argument (as a wrapper can do) so it just spreads out the class to fmt::format{} which, being C++, uses variadic templates to receive the arguments. The main motivation for this function to able to format string as use by the ‘fmtlib::fmt’ library included in ‘spdlog’ to write similar debug strings in both R and C++. This function permits R calls with multiple arguments of different types which (by being formatted on the R side) are handled as strings (whereas C++ logging has access to the templating logic).

Usage

formatter(s, v)

Arguments

Value

A single (formatted) string

See Also

https://github.com/fmtlib/fmt

R Accessor Functions for spdlog Stopwatch

Description

A set of functions provides access to the spdlog stopwatch facilty. As stopwatch object is a simple container around a C++ std::chrono object which (essentially) reports elapsed-time since creation. The object is exported to R via an external pointer permitting use from both R and C++.

Usage

get_stopwatch()

elapsed_stopwatch(sw)

format_stopwatch(sw)

## S3 method for class 'stopwatch'
print(x, ...)

## S3 method for class 'stopwatch'
format(x, ...)

Arguments

Details

Several functions are provided:

get_stopwatch

Returns a stopwatch object (as an S3 object).

elapsed_stopwatch

Returns elapsed time for stopwatch in seconds.

format_stopwatch

Returns elapsed time for stopwatch as character variable.

The stopwatch object has print and format methods.

Value

The desired object is returned: respectively, a stopwatch object as an external pointer in an S3 class, the elapsed time in seconds as a double, or formatted as a character variable.

Examples

w <- get_stopwatch()
Sys.sleep(0.2)
elapsed_stopwatch(w)
format_stopwatch(w)

R Accessor Functions for spdlog Logger

Description

Several R-level functions can access the spdlog logging facilties. As spdlog is a C++-level logging library, these are R function permit concurrent logging from both R and C++.

Usage

log_setup(name = "default", level = "warn")

log_init(level = "warn")

log_filesetup(filename, name = "default", level = "warn")

log_drop(name)

log_set_pattern(s)

log_set_level(s)

log_trace(s)

log_debug(s)

log_info(s)

log_warn(s)

log_error(s)

log_critical(s)

Arguments

Details

Several functions are provided:

log_setup

Initializes a logger (which becomes the default logger).

log_filesetup

Initializes a file-based logger (which becomes the default).

log_drop

Removes logger (which in general should not be needed).

log_set_pattern

Changes the default logging message pattern.

log_set_level

Sets the logging level threshold.

log_trace

Logs a trace-level message.

log_debug

Logs a debug-level message.

log_info

Logs a info-level message.

log_warn

Logs a warn-level message.

log_error

Logs a error-level message.

log_critical

Logs a critical-level message.

Supported logging levels are, in order of increasing threshold values, ‘trace’, ‘debug’, ‘info’, ‘warn’, ‘error’, and ‘critical’. A message issued below the current threshold is not displayed whereas a message at or above the current threshold is displayed. The default level is ‘warn’.

Value

Nothing is returned from these functions as they are invoked for their side-effects.

See Also

The logging pattern format is described in at the repo in the page https://github.com/gabime/spdlog/wiki/3.-Custom-formatting.

Examples

log_setup("demo")  # at default level 'warn'
log_info("this message is NOT seen")
log_set_level("debug")
log_info("this message is seen")
log_warn("as is this message")

spdlog Logging Lever Setter

Description

A helper function to turn a logging level given as string into the current logging level

Usage

setLogLevel(name)

Arguments

Value

Nothing is returned.